Intake manifold



Nov. 27, 1956 D. F. cARls ETAL 2,771,864

INTAKE MANIFOLD Filed Dec. 3o, 1954 i Omey INTAKE MANnsoLD Darl F. Cai-is, Bloomfield Hills, and Fred Davis, Romeo,

Mich., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application December 30, 1954, Serial No. 473,641

13 Claims. (Cl. 12S-52) The present invention relates to internal combustion engines and more particularly to induction systems therefor.

In the operation of an internal combustion engine, the combustible charge is normally formed by drawing air through a fuel mixing device such as a carburetor. The fuel is then atomized into the air and the resultant charge is distributed to the various cylinders in the engine by means of an intake manifold. In order to obtain the maximum power, it is desirable that the induction system present the least amount of resistance to the ow of the charge into the cylinders to thereby obtain a high volumetric efficiency. Since the carburetor normally employs a venturi to assist in atomizing the fuel, a considerable proportion of the flow resistance occurs in the carburetor. Therefore, numerous attempts have been made to improve the volumetric eiiiciency by employing a multiplicity of carburetors. However in such systems, it has been dilicult to insure each of the cylinders obtaining uniform charges because the distance from the carburetors to the cylinders are not equal.

It is now proposed to provide an intake manifold which is particularly adapted for employing a multiplicity of carburetors. This manifold may have a central chamber into which the carburetors discharge. In the present instance this chamber comprises an endless distribution passage that forms a loop or oval and is interconnected with the various combustion chambers by a plurality of individual branch passages. The carburetors may be mounted on the opposite ends of the manifold to cornmunicate directly with the distribution passages. If the branch passages are disposed between the carburetors, the total distance from each of the branch passages to the carburetors will always be equal. Thus the charge may be drawn through a plurality of carburetors thereby insuring a high volumetric eiciency at all times.

When a multiplicity of carburetors is employed, it is difficult to obtain proper carburization at all engine loads. If the carburetors are made large enough to operate most efliciently at or near full load, they will not function properly at idle or low speeds as the volume of air ow is too small.

It is now proposed to provide an intake manifold which will employ a plurality of large high-speed carburetors and a low-speed or idle carburetor. The idle carburetor is adapted to operate efficiently at low speed. This carburetor is connected to the cylinders by an independent set of distribution and branch passages. The high speed carburetor may also be connected to the cylinders by another independent set of distribution and branch passages. Thus when the demand for the charge is small only the idle carburetor will function thus insuring good carburetion. However, when the demand becomes large, the high-speed carburetors will function to produce a charge with a minimum amount of How resistance. Thus the carburetors for high operation speed may be of adequate capacity to insure optimum operation 2,771,864 Patented Nov. 27, 1956 at high speeds while an independent low speed carbureting means is also supplied that is particularly adapted to operate at low engine speeds without impairing full load or high speed operation.

In the one sheet of drawings, Figure 1 is a plan view of an engine employing an intake manifold embodying the present invention, portions thereof being broken away.

Referring to the drawings in more detail, the present invention may be incorporated in an intake manifold 10 adapted for use on any type of engine 12. However for the purposes of illustration only, the manifold 10 shown is particularly adapted for use on a so-called V-type engine. The engine 12 may include a cylinder block 14 containing two banks 16 and v18 of cylinders with each bank having four cylinders. The banks 16 and 18 are angularly disposed with respect to each other and form a space therebetween.

Cylinder heads 20 and 22 may be secured to each of these banks of cylinders. The heads 20 and 22 may have cavities therein which register with the open ends of the cylinders for forming a plurality of combustion chambers. Intake passages may extend through the heads with the inner ends communicating with the combustion chamber and the outer ends forming intake ports 24 on the inside faces 26 and 28 of the heads 20 and 22,

A cooling system may be provided in order to cool various portions of the engine 12 and more particularly the walls of the combustion chamber. A coolant manifold 30 may extend transversely of the engine 12 between the heads 20 and 22 to interconnect the cooling system with a radiator.

An induction system 32 may be provided for delivering a combustible charge to the various combustion chambers. In the present instance this induction system 32. includes the intake manifold 10 which is disposed in the space between the heads 20 and 22. The opposite sides of the manifold 10 may have longitudinally extending surfaces 34 and 36 that are positioned to engage the faces 26 and 2e on the cylinder heads 20 and 22 and be secured thereto by means of bolts 38.

A plurality of carburetor risers it) and 42 may be provided on the intake manifold 10. Although carburetors of any suitable type may be employed in the present instance these risers 4) and 42 are adapted to receive a so-called downdraft carburetors. The risers 4@ and 42 may be disposed at the opposite ends of the intake manifold 10 and include flanges 44 and i6 that extend therearound for mounting the carburetor thereon. A substantially vertical fuel supply passage 48 and 50 may extend through each riser 4i) and 42 to form an opening in the flanges 44 and 46. Although each of the risers 4t) and 42 and carburetors may have any number of passages therein, it is preferable that each riser and carburetor have only one passage which is large enough to adequately handle the combustible charge at full load.

A distribution chamber may be formed in the center of the manifold that communicates with the fuel supply passages 48 and Sti extending through the risers it? and 42. Although this chamber could be of any suitable shape, in the present instance it is an endless passage 52. having a generally oval shape. Thus the charge may flow through either one or both of the risers ttl and i2 into this distribution passage S2 and circulate therethrough.

Branch passages 54 may extend through the manifold 10 with the inner ends thereof intersecting the distribution passage 52. In the present instance the intake ports are grouped in pairs and accordingly, the branch passages are correspondingly paired to intersect the distribution passages at four separate points. These points are preferably disposed adjacent the vends of the distribution passage so as to be close to one of the carburetors. However, irrespective of where the passages 54 intersect the distribution passage 52, the sum of the distances between the two carburetors and the passages will be equal. The outer ends of the branch passages 54 may form ports in the sides of the manifold 10 to register with the intake ports 24. It is preferable that the branch passages 54 are all of equal length. Thus the distance from the carburetors to the intake ports will be equal.

A carburetor riser 56 may be provided in the middle of the manifold 10 similar to the end risers 4l) and 42, however, it may be smaller. A vertical fuel supply passage S may extend through the riser 56 to form an opening in the mounting ange S9 that registers with the fuel mixing passage in the carburetor. A plurality of distribution passages 60 may radiate horizontally from the lower end of the fuel supply passage 58 in this riser 56. Each of these distribution passages 60 extend toward the intake ports 24 with each distribution passage 60 dividing into separate branch passages 62 that terminate adjacent the intake ports 24. Thus the charge from the center carburetor may flow through the distribution passages 60 and branch passages 62 into the intake passages 24. It should be no-ted that the particular disposition of these passages may vary to fit any particular requirements.

When the engine 12 is operating at idle or near idle speeds, the air may enter the induction system 32 through the center carburetor. This carburetor may be particularly adapted for handling the small quantities of air required under such light loads. Thus if the larger carburetors on the ends of the manifold are inoperative, proper carburization of the fuel will be insured. The charge formed in this carburetor may then flow through the distribution passage S2 and the branch passages and thereby iiow to the cylinders. As the load on the engine l2 is increased, the throttle valve in the center carburetor will open. When this opening progresses to the point where the demand is large enough to insure proper operation of the large carburetors, the throttle valve control linkage may cause the throttle valves in the large carburetors to commence opening. Thus when the engine is fully loaded, the throttle valves in the larger carburetors will be fully opened. It should be noted that it is not necessary for the large carburetors to operate at light loads. Thus they may be particularly adapted to handle the heavy demands of full load without impairing the idling characteristics of the engine as the idle carburetor will satisfy that load.

It is thus apparent that during low speed operation of the engine, a small size carburetor may be provided which is capable of functioning properly even at the small loads imposed thereon during low speed operation. At the same time when the load of the engine becomes large enough, a charge may flow through the end carburetors which are of adequate capacity to insure the maximum output from the engine. ln addition, since the distances from the carburetors to the distribution passages are all equal, the load delivered to each of the cylinders will be uniform.

It is to be understood that, although the invention has been described with specific reference to a particular embodiment thereof, it is not to be so limited since changes and alterations therein may be made which are within the full intended scope of this invention as defined by the appended claims.

What is claimed is:

l. An intake manifold comprising a member having a distribution chamber formed in the middle thereof, fuel supply passages communicating with said chamber substantially normal thereto, a plurality of branch passages extending through said manifold, the inner ends of said branch passages communicating with said distribution chamber and the outer ends 'thereof forming ports inthe sides of said manifold.

2. An intake manifold .comprising a member having an endless distribution passage, at least a pair of carburetor risers having fuel supply passages intersecting said distribution passage at substantially right angles thereto, said member having branch passages extending therethrough with the inner ends of said branch passages intersecting said distribution passage and the outer ends forming ports in the sides of said member.

3. An intake manifold for use on an engine having a pair of angularly disposed banks of cylinders, said manifold comprising a member having a distribution chamber formed in the middle thereof, said member having fuel supply passages adjacent the opposite ends thereof communicating with said distribution chamber at substantially right angles to the flow therein, said member including branch passages on the opposite sides thereof, the inner ends of said branch passages communicating with said distribution chamber and the outer ends forming ports in the opposite sides of said member.

4. An intake manifold for use on an engine having a pair of angularly disposed banks of cylinders, said manifold comprising a member having an endless distribution passage, carburetor risers adjacent the opposite ends of said member and having fuel supply passages communieating with said distribution passage substantially normal thereto, said member having branch passages on the opposite sides thereof, the inner ends of said branch passages communicating with said distribution passage and the outer ends forming ports in the opposite sides of said member.

5. An intake manifold for use on an engine having a pair of angularly disposed banks of cylinders, said manifold comprising a member having an endless distribution passage including a pair of side portions extending longitudinally of said member and a pair of end portions extending transversely of said member, carburetor risers adjacent the ends of said member and having fuel supply passages communicating with said transverse portions at substantially right angles thereto, branch passages having the inner ends communicating with said distribution passage and the outer ends forming ports in the sides of said member.

6. An intake manifold for use on an engine having a pair of angularly disposed banks of cylinders, said manifold comprising a member having a carburetor riser disposed in the middle thereof and having a fuel supply passage, distribution passages communicating with said fuel supply passage and radiating therefrom, the outer ends of said distribution passages dividing to form separate outlet ports on the sides of said member for said cylinders.

7. An intake manifold for use on an engine having a pair of angularly disposed banks of cylinders, said manifold comprising a rst portion having ports adapted to supply a charge for said engine, a second portion having a carburetor riser disposed in the middle thereof, a vertical fuel supply passage and horizontally disposed distribution passages, the inner ends of said distribution passages communicating with the lower end of said fuel supply passage, the outer ends of said distribution passages dividing into separate branch passages that form outlets adjacent said ports for supplying another charge separate from said first charge.

8. An intake manifold for an engine comprising a member including a distribution chamber having at least one fuel supply passage communicating therewith a plurality of branch passages having the inner ends thereof communicating with said distribution chamber and the outer ends thereof forming ports in the sides lof said member for supplying a charge to said engine, said member including a second fuel supply passage disposed in the middle thereof, distribution passages having the inner ends thereof communicating with -sad last mentioned Ifuel supply passage and the outer ends terminating ladjacent said ports .for supplying another charge .to said engine.

9. An intake manifold for use on an ,engine having a wel" pair of angularly disposed banks of cylinders, said manifold comprising a member having an endless distribution passage, carburetor risers adjacent the opposite ends of said member communicating with said distribution passage, branch passages on the opposite sides of said member communicating with said distribution passage and forming ports in the opposite sides of said member, a carburetor riser disposed in the middle of said member and having a fuel supply passage therein, and distribution passages having the inner ends thereof communicating with said last mentioned fuel supply passage and the outer ends thereof terminating adjacent said ports.

10. An intake manifold for use on an engine having a pair of angularly disposed banks of cylinders, said manifold comprising a member having an endless distribution passage, carburetor risers adjacent the opposite ends of said member and having fuel supply passages communicating with said distribution passage, branch passages having the inner ends thereof communicating with said distribution passage and the outer ends forming ports in the opposite sides of said member, a earburetor riser disposed in the middle of said member and having a substantially vertical fuel supply passage therein, distribution passages horizontally disposed in said member with the inner ends thereof communicating with the lower end of said last mentioned fuel supply passage, the outer ends of said last mentioned distribution passages dividing into separate branch passages that terminate adjacent said ports.

1l. An intake manifold for use on an engine having a pair of angularly disposed banks of cylinders, said manifold comprising a member having an endless distribution passage including a pair of side portions extending longitudinally of said member and a pair of end portions extending transversely of said member, carburetor' risers adjacent the opposite ends of said member and having fuel supply passages communicating with said transverse portions, branch passages having the inner ends thereof communicating with said distribution passages and the outer ends thereof forming ports in the sides of said member, a carburetor riser disposed in the middle of said member and having a substantially vertical fuel supply passage therein, distribution passages having the inner ends thereof communicating with said fuel supply passage and the outer ends thereof terminating adjacent said ports.

l2. An intake manifold for use on an engine having a pair of angularly disposed banks of cylinders, said manifold comprising a member having an endless distributicn passage including a pair of side portions extending longitudinally of said member and a pair of end portions extending transversely of said member, carburetor risers adjacent the opposite ends of said member and having substantially vertical fuel supply passages communicating with said transverse portions, branch passages having the inner ends thereof communicating with said distribution passage and the outer ends forming ports in the sides of said member, a carburetor riser disposedl in the middle of said carburetor and having a substantially vertical fuel supply passage therein, distribution passages horizontally disposed in said member and having the inner ends thereof communicating with the lower end of said last mentioned fuel supply passage, the outer ends of said last mentioned distribution passages dividing into separate branch passages that form ports in the sides of said member.

13. An intake manifold for use on an engine having a pair of angularly disposed banks of cylinders, said manifold comprising a member having a distribution chamber formed therein, at least one carburetor riser communicating with said distribution chamber, branch passages communicating with said distribution chamber and forming ports in the opposite sides of said member, a carburetor riser disposed in the middle of said member and having a fuel supply passage therein, and a second set of branch passages having the inner ends thereof communicating with said last mentioned fuel supply passage and the other ends thereof terminating adjacent said ports.

References Cited in the le of this patent UNITED STATES PATENTS 2,098,424 Kolimbat Nov. 9, 1937 2,272,418 Mery Feb. 10, 1942 

